1. Field of the Invention
The present invention relates to an absorption refrigerating machine capable of circulating solution efficiently, and more particularly, it relates to a double effect absorption refrigerating machine in which a flow rate of a diluted solution circulating through high and low temperature generators is controlled to achieve effective performance, and a double effect absorption cold or hot water generating machine controlled in a corresponding manner.
2. Prior Art
Conventionally, the coefficient of heat recovery of heat exchangers had to be increased in order to improve the efficiency (COP; coefficient of result) of refrigerating machines. In this case, however, pressure loss of the heat exchangers had a tendency to be increased. For example, in a conventional absorption refrigerating machine, as shown in FIG. 3, since the solution is not completely returned to an absorber A, if pressure loss of a low temperature heat exchanger XL is increased, a J line shown by the broken line is provided to return the solution directly from the low temperature generator to the absorber, and the solution is often returned through the J line. In this case, however, the efficiency is considerably lowered. To avoid this, as shown in FIG. 4, a solution spray pump P.sub.3 is provided for backing up the pressure. In this case, however, since the solution to be circulated is circulated by the single solution spray pump, an amount of solution circulating through the respective circuits cannot be adjusted independently and a problem arises in respect to how to adjust the circulating solution.
In normal absorption refrigerating machines, a heat amount of a heat source is adjusted on the basis of a cooling load signal or a cold water temperature signal. Further, in double effect absorption refrigerating machines, the difference in pressure and positional head between a high temperature generator and an absorber provide a driving force for flowing solution from the high temperature generator to the absorber. In general, the flow resistance in solution paths is adjusted (for example, by providing orifices) to obtain desired flow rate under the action of a driving force in a rated condition.
In this way, when the pressure in the high temperature generator is changed, since the above-mentioned driving force is also changed, an amount of solution flowing out of the high temperature generator is changed. A flow-in amount of solution flowing into the high temperature generator is adjusted to compensate for the amount of solution flowing out of the high temperature generator. In order to adjust such a flow-in amount, conventionally, a regulating valve was provided in a diluted solution path between an absorber and a generator, as disclosed in the JP-U-54-182458 (Japanese Utility Model Laid-open No. 182458/79). By the way, although the amount of solution circulating through a low temperature generator is associated with pressure and temperature of the high temperature generator, in the past, a technique in which the pressure and temperature of the high temperature generator is controlled by controlling the amount of solution circulating through the low temperature generator had not been effected.